Studies on the evolution of characters in the cephalochordates, based on molecular trees of many living species over the world

本项目收集的标本中，有超过一半（全球15种24个居群）的线粒体全基因组进行了分析，取得了以下重要成果：(1)揭示了lucayanus epiigonichthys的独特性。(2) Epigonichthys属的准枝性已得到证实，其中E.lucayanus（及其隐种，见下文）与其余（由其同系物和另一个公认的Branchiostoma属的种组成）之间的分支最深；因此，头脊索目已被证明分为三个属（而不是目前系统中的两个）。(3)发现lucayanus有两种，在形态上彼此难以区分。(4)欧洲lancelet， Branchiostoma lanceolatum在分子信息数据库中的分子数据显示与Helgoland和Napoli的同一种分析有很大差异，而与佛罗里达B.floridae的分子数据相似；这种差异是由于对银行数据的错误识别造成的。

We have analyzed the whole mitochondrial genomes of far more than the half of the samples gained during the present project (24 populations of 15 species over the world) and got many important results as follows :(1) The uniqueness of Epigonichthys lucayanus has been revealed.(2) Paraphyly of the genus Epigonichthys has been proved, with the deepest branching between E.lucayanus (and its cryptic species, see below) and the remaining (consisting of its congeners and the species of the other recognized genus Branchiostoma) ; thus the Cephalochordata has proved to be divided into the three (instead of the two in the present system) genera.(3) E.lucayanus has been found to contain two species, which are indistinguishable morphologically from each other.(4) Molecular data of the European lancelet, Branchiostoma lanceolatum registered in the data bank of molecular information has been revealed quite different from our analyses of the same species from Helgoland and Napoli, instead similar to that of B.floridae from Florida ; this discrepancy is attributable to mis-identification of the data in the bank.